1. Field
The disclosed concept relates generally to circuits, and in particular, to circuits for driving actuators.
2. Background Information
Magnetic actuators, such as those used in circuit breakers, have an underlying circuitry in order to drive it. Some types of actuators are bi-stable, meaning that they will remain in their current state when power is removed. Bi-stable actuators generally have a closing coil and an opening coil. Current passing through the closing coil will cause the actuator to move to a closed state and current passing through the opening coil will cause the actuator to move to the open state.
FIG. 1 shows an example of one type of circuit used for driving a bi-stable actuator having a closing coil 1 and an opening coil 2. The closing coil 1 and the opening coil 2 are depicted in the circuit diagram shown in FIG. 1. The circuit of FIG. 1 includes three transistors. Applying control signals to the gates of the transistors controls whether current flows through the closing coil 1 or the opening coil 2. In addition to the three transistors, the circuit of FIG. 1 further includes six diodes and a power resistor.
FIG. 2 shows an example of a second type of circuit used for driving a bi-stable actuator having a closing coil 1 and an opening coil 2. The circuit shown in FIG. 2 is similar to the circuit disclosed in Chinese Patent No. 202917401. The circuit of FIG. 2 includes four transformers. Applying control signals to the gates of the transistors controls whether current flows through the closing coil 1 or the opening coil 2. In addition to the four transistors, the circuit of FIG. 2 further includes four diodes and a capacitor.
Although the circuits of FIGS. 1 and 2 can be used to drive a bi-stable actuator, it would be desirable to reduce the number of circuit components used to drive a bi-stable actuator, as each circuit component adds to cost. There is room for improvement in circuits for driving bi-stable actuators.